Effects Of Different Water And Nitrogen Control Pattern On Growth, Water And Nitrogen Use Efficiency Of Dryland Winter Wheat

Water shortage and poor soil were two key factors that limited the efficient developmentof northwest dryland agriculture. How to improve the use efficiency of existing waterresources. At the same time, saving resources and improving crop yield had been the hot spot.Water and fertilizer coupling under the conditions of limited water resource was an effectiveway to improve the use efficiency of dryland water resources and promote the sustainabledevelopment of agriculture of our country.At the same time, in dry farming the mainagronomic measures to make crops high-efficient and high-yield was straw covering to keepmoisture and water conservation measures and limited irrigation technology. However, theseresearches were to consider a single factor or two factors, and there is few reports on theimpact of comprehensive consideration of N application rate, irrigation amount and irrigationtime, and straw mulching.Winter wheat was the object of this test. We analysed the effect of moisture regulationand control under the conditions of different N rate on the growth of wheat and theaccumulation, transfer and use of nitrogen, water use efficiency and yield and its influencefactors.It is supposed to select suitable pattern for local conditions of winter wheat efficientwater management technology. We had the following main conclusions:1. The yield of winter wheat can get a higher level when the N application rate was150kg/hm~2.If we Increased N application, The yield could not increas significantly and It wouldbe easy to cause the waste of nitrogen fertilizer. Straw mulching+jointing stage irrigation canimprove the winter wheat grain yield very well.2.Nitrogen application significantly improved the above ground and grain nitrogenaccumulation amount of wheat. However, excessive application (N225) led to0~200cm soilnitrate nitrogen residual and nitrogen use efficiency decreasing significantly.3.The use efficiency of water increased with the increase of N rate.It did not significantlyimprove the water use efficiency of winter wheat with too much nitrogen fertilizer; Themoisture control model to cover+jointing stage mending irrigation treatment and jointingstage mending irrigation treatment can promote the water use efficiency of winter wheat verywell. 4.Nitrogen fertilizer could significantly improve the chlorophyll content andphotosynthesis efficiency of functional leaf of winter wheat. However, the result was notsignificant with too much nitrogen. Straw mulching combined with late jointing stageirrigation was good at the development in the process of the synthesis of chlorophyll anddelayed the senescence of leaves, extended leaf photosynthetic time during winter wheatgrowth.5. Under appropriate n rate straw mulching+jointing stage irrigation and strawmulching+over-wintering stage mending irrigation treatments could reduce the soil bulkdensity and soil compactness, improve the available nitrogen, total nitrogen and organicmatter content of top layer, increase soil urease and phosphatase activity. It effectivelyimproved the soil physical and chemical and biological properties.